Bioinspired Nanocomposites with Self-Adaptive Stress Dispersion for Super-Foldable Electrodes.

In flexible electronics, appropriate inlaid structures for stress dispersion to avoid excessive deformation that can break chemical bonds are lacking, which greatly hinders the fabrication of super-foldable composite materials capable of sustaining numerous times of true-folding. Here, mimicking the microstructures of both cuit cocoon possessing super-flexible property and Mimosa leaf featuring reversible scatheless folding, super-foldable C-web/FeOOH-nanocone (SFCFe) conductive nanocomposites are prepared, which display cone-arrays on fiber structures similar to Mimosa leaf, as well as non-crosslinked junctions, slidable nanofibers, separable layers, and compressible network like cuit cocoon. Remarkably, the SFCFe can undergo over 100 000 times of repeated true-folding without structural damage or electrical conductivity degradation. The mechanism underlying this super-foldable performance is further investigated by real-time scanning electron microscopy folding characterization and finite-element simulations. The results indicate its self-adaptive stress-dispersion mechanism originating from multilevel biomimetic structures. Notably, the SFCFe demonstrates its prospect as a super-foldable anode electrode for aqueous batteries, which shows not only high capacities and satisfactory cycling stability, but also completely coincident cyclic voltammetry and galvanostatic charge-discharge curves throughout the 100 000 times of true-folding. This work reports a mechanical design considering the self-adaptive stress dispersion mechanism, which can realize a scatheless super-foldable electrode for soft-matter electronics.